Egg cartons are subjected to multiple adverse mechanical forces and environmental conditions during filling, handling, transport and use, including time spent in distribution centers, on store shelves, and in the consumer's home. They typically encounter automated equipment for filling, packaging, loading, unloading, stacking, restacking and transport. During each of these encounters, the goal is to resist egg breakage by stabilizing and holding the eggs in a protected environment, in a carton that can be manufactured in a cost effective manner.
Thus, many factors are taken into consideration in the design of egg cartons. Egg protection, resistance to stress or force, stackability, transportability, moisture resistance, aesthetic appearance, print surface area, weight, nestability/denestability, adaptability to accommodate various size eggs, and consistent manufacturing are factors which may be considered to varying degrees in the design of an egg carton.
Plastic egg cartons are available with flexible walls forming cell pockets to protect the eggs and prevent them from moving into adjacent cell pockets. However, during handling, such as while loading cases of egg cartons onto a grocery pallet, and then stacking cases 5 to 6 high on the pallet, the cases/cartons may be thrown onto the pallets and/or bump into each other, causing the eggs to come out of their cell pockets and make contact from a hard side impact blow or top compression load. Also, when scanning bar codes on lid tops, the eggs can be displaced and make contact.
Thus, there is need for an improved egg carton construction to provide better egg protection while encountering the adverse mechanical forces and environmental changes that typically occur during filling, packaging, transportation, storage and use. At the same time, there is a need to manufacture such cartons in a cost effective manner and to maintain overall carton dimensions to fit within standard case sizes and to avoid a redesign of the existing automated filling and handling equipment.